A brilliant and intriguing game bar a couple of low points
The whole concept is brilliant and original; walking upside down, the use of portals and puzzles abound make this one of the greatest and innovative video games of all time. And the spirit walk function makes it incredibly fun to play.
I hate dying all the time; even with the spirit world mode it still annoys the heck of me; limited skill setting options means there is no way to play a relaxed game free of frustration thanks to the lack of an easy mode. Of course, there's cheat codes for the game, but they simply make it boring. It is a bit boring to begin with too, so don't let the demo put you off; it only gets better the more you progress through the game.
The Bottom Line
Get it, get it, get it. Bar a few annoyances you will not be sorry. I promise you this.